The present invention relates to an automatic winding machine for manufacturing an air core coil insertable to a core installed in a rectifying circuit, a noise prevention circuit, a resonance circuit, and the like in various AC devices. The present invention also relates to an air core coil including a plurality of coil layers, and a winding method of the same.
A coil device installed in the rectifying circuit, the noise prevention circuit, the resonance circuit, and the like of the AC devices is formed by winding a coil around a core.
The applicant proposed a method of manufacturing a coil device by inserting an air core coil preliminarily wound in a spiral form to a core in which a gap is opened in the tangential direction from the gap (for example, refer to Patent Document 1: Japanese Patent Laid-open Publication No. 2000-277337).
An automatic winding machine of Patent Document 1 described above includes a pair of winding core members having a substantially rectangular section and being integrally rotated by a rotation drive mechanism, and manufactures an air core coil in which an inner circumferential length on the inner circumferential side of the core and an outer circumferential length on the outer circumferential side of the core are different by rotating while changing an interval between the winding core members and directly winding a conductive wire around the winding members.
As a method of manufacturing an air core coil in which an inner circumferential length and an outer circumferential length are different, a method of using a stepped winding jig corresponding to a hollow shape of the air core coil (Patent Document 2: Japanese Patent Laid-open Publication No. 2003-86438) and an automatic winding machine for winging a conductive wire around a winding core member while changing a form of the winding core member for each wire winding step of a unit wound portion (Patent Document 3: Japanese Patent Laid-open Publication No. 2006-339407) are known.
When the air core coil manufactured by an automatic winding machine of Patent Document 2 or 3 described above is installed to a core, a part of the conductive wire on the inner circumferential side of the core is overlapped in the radial direction, so that the conductive wire can be closely wound.
As shown in FIG. 15, an air core coil 200 in which unit coil portions 23 formed by winding a conductive wire 22 in a swirl form are repeatedly placed side by side in the winding shaft direction can be obtained.
As a winding method of such an air core coil 200, a method of forming a first unit wound portion 25, a second unit wound portion 26, and a third unit wound portion 27 having different inner circumferential lengths from each other continuously in the winding shaft direction by winding a conductive wire in a swirl form as shown in FIG. 16(a), and forming unit coil portions including the plurality of unit wound portions 25, 26, 27 continuously in the winding shaft direction, so as to manufacture an interim product of the air core coil, and then compressing the interim product in the winding shaft direction, pushing at least a part of the second unit wound portion 26 inside the third unit wound portion 27, and pushing at least a part of the first unit wound portion 25 inside the second unit wound portion 26 as in FIG. 16(b), so as to obtain a finished product of the air core coil including a plurality of coil layers (three layers in the example of the figure) is known (Patent Document 2).